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From: John Stultz <john.stultz@linaro.org>
To: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Arnd Bergmann <arnd@arndb.de>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	xen-devel@lists.xensource.com, Ian.Campbell@citrix.com,
	Peter Zijlstra <peterz@infradead.org>,
	lkml <linux-kernel@vger.kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@kernel.org>
Subject: Re: [PATCH v2 1/7] timekeeping: introduce __current_kernel_time64
Date: Tue, 10 Nov 2015 07:26:01 -0800	[thread overview]
Message-ID: <CALAqxLUEOWP6CJxY021nDR6cEQf3VZtm8fa9waK2a=OmQJEO-g@mail.gmail.com> (raw)
In-Reply-To: <alpine.DEB.2.02.1511101507540.5676@kaball.uk.xensource.com>

On Tue, Nov 10, 2015 at 7:10 AM, Stefano Stabellini
<stefano.stabellini@eu.citrix.com> wrote:
> On Tue, 10 Nov 2015, Arnd Bergmann wrote:
>> On Tuesday 10 November 2015 11:57:49 Stefano Stabellini wrote:
>> > __current_kernel_time64 returns a struct timespec64, without taking the
>> > xtime lock. Mirrors __current_kernel_time/current_kernel_time.
>> >
>>
>> Actually it doesn't mirror __current_kernel_time/current_kernel_time
>>
>> > diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h
>> > index ec89d84..b5802bf 100644
>> > --- a/include/linux/timekeeping.h
>> > +++ b/include/linux/timekeeping.h
>> > @@ -19,7 +19,8 @@ extern int do_sys_settimeofday(const struct timespec *tv,
>> >   */
>> >  unsigned long get_seconds(void);
>> >  struct timespec64 current_kernel_time64(void);
>> > -/* does not take xtime_lock */
>> > +/* do not take xtime_lock */
>> > +struct timespec64 __current_kernel_time64(void);
>> >  struct timespec __current_kernel_time(void);
>>
>> Please change __current_kernel_time into a static inline function
>> while you are introducing the new one, to match the patch description ;-)
>
> The implementation is:
>
>         struct timekeeper *tk = &tk_core.timekeeper;
>
>         return timespec64_to_timespec(tk_xtime(tk));
>
> which cannot be easily made into a static inline, unless we start
> exporting tk_core.

So the timekeeper is passed to the notifier. So you probably want something like

struct timespec64 __current_kernel_time64(struct timekeeper *tk)
{
 return timespec64_to_timespec(tk_xtime(tk));
}

Then you can cast the priv pointer in the notifier to a timekeeper and
use it that way?

thanks
-john

WARNING: multiple messages have this Message-ID (diff)
From: john.stultz@linaro.org (John Stultz)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 1/7] timekeeping: introduce __current_kernel_time64
Date: Tue, 10 Nov 2015 07:26:01 -0800	[thread overview]
Message-ID: <CALAqxLUEOWP6CJxY021nDR6cEQf3VZtm8fa9waK2a=OmQJEO-g@mail.gmail.com> (raw)
In-Reply-To: <alpine.DEB.2.02.1511101507540.5676@kaball.uk.xensource.com>

On Tue, Nov 10, 2015 at 7:10 AM, Stefano Stabellini
<stefano.stabellini@eu.citrix.com> wrote:
> On Tue, 10 Nov 2015, Arnd Bergmann wrote:
>> On Tuesday 10 November 2015 11:57:49 Stefano Stabellini wrote:
>> > __current_kernel_time64 returns a struct timespec64, without taking the
>> > xtime lock. Mirrors __current_kernel_time/current_kernel_time.
>> >
>>
>> Actually it doesn't mirror __current_kernel_time/current_kernel_time
>>
>> > diff --git a/include/linux/timekeeping.h b/include/linux/timekeeping.h
>> > index ec89d84..b5802bf 100644
>> > --- a/include/linux/timekeeping.h
>> > +++ b/include/linux/timekeeping.h
>> > @@ -19,7 +19,8 @@ extern int do_sys_settimeofday(const struct timespec *tv,
>> >   */
>> >  unsigned long get_seconds(void);
>> >  struct timespec64 current_kernel_time64(void);
>> > -/* does not take xtime_lock */
>> > +/* do not take xtime_lock */
>> > +struct timespec64 __current_kernel_time64(void);
>> >  struct timespec __current_kernel_time(void);
>>
>> Please change __current_kernel_time into a static inline function
>> while you are introducing the new one, to match the patch description ;-)
>
> The implementation is:
>
>         struct timekeeper *tk = &tk_core.timekeeper;
>
>         return timespec64_to_timespec(tk_xtime(tk));
>
> which cannot be easily made into a static inline, unless we start
> exporting tk_core.

So the timekeeper is passed to the notifier. So you probably want something like

struct timespec64 __current_kernel_time64(struct timekeeper *tk)
{
 return timespec64_to_timespec(tk_xtime(tk));
}

Then you can cast the priv pointer in the notifier to a timekeeper and
use it that way?

thanks
-john

  reply	other threads:[~2015-11-10 15:26 UTC|newest]

Thread overview: 67+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-11-10 11:56 [PATCH v2 0/7] Xen wallclock on arm and arm64 Stefano Stabellini
2015-11-10 11:56 ` Stefano Stabellini
2015-11-10 11:56 ` Stefano Stabellini
2015-11-10 11:57 ` [PATCH v2 1/7] timekeeping: introduce __current_kernel_time64 Stefano Stabellini
2015-11-10 11:57   ` Stefano Stabellini
2015-11-10 11:57   ` Stefano Stabellini
2015-11-10 12:22   ` Peter Zijlstra
2015-11-10 12:22     ` Peter Zijlstra
2015-11-10 14:34     ` Stefano Stabellini
2015-11-10 14:34       ` Stefano Stabellini
2015-11-10 14:34       ` Stefano Stabellini
2015-11-10 12:29   ` Arnd Bergmann
2015-11-10 12:29     ` Arnd Bergmann
2015-11-10 12:29     ` Arnd Bergmann
2015-11-10 15:10     ` Stefano Stabellini
2015-11-10 15:10       ` Stefano Stabellini
2015-11-10 15:10       ` Stefano Stabellini
2015-11-10 15:26       ` John Stultz [this message]
2015-11-10 15:26         ` John Stultz
2015-11-10 15:26         ` John Stultz
2015-11-10 15:31         ` Thomas Gleixner
2015-11-10 15:31           ` Thomas Gleixner
2015-11-10 15:31           ` Thomas Gleixner
2015-11-10 15:41           ` John Stultz
2015-11-10 15:41             ` John Stultz
2015-11-10 15:41             ` John Stultz
2015-11-10 15:55             ` Thomas Gleixner
2015-11-10 15:55               ` Thomas Gleixner
2015-11-10 15:55               ` Thomas Gleixner
2015-11-11 11:51               ` Stefano Stabellini
2015-11-11 11:51                 ` Stefano Stabellini
2015-11-11 11:51                 ` Stefano Stabellini
2015-11-11 13:31                 ` Arnd Bergmann
2015-11-11 13:31                   ` Arnd Bergmann
2015-11-11 13:31                   ` Arnd Bergmann
2015-11-10 11:57 ` [PATCH v2 2/7] xen: rename dom0_op to platform_op Stefano Stabellini
2015-11-10 11:57   ` Stefano Stabellini
2015-11-10 11:57   ` Stefano Stabellini
2015-11-10 11:57 ` [PATCH v2 3/7] xen/arm: introduce HYPERVISOR_platform_op on arm and arm64 Stefano Stabellini
2015-11-10 11:57   ` Stefano Stabellini
2015-11-10 11:57   ` Stefano Stabellini
2015-11-10 11:57 ` [PATCH v2 4/7] xen: introduce XENPF_settime64 Stefano Stabellini
2015-11-10 11:57   ` Stefano Stabellini
2015-11-10 11:57   ` Stefano Stabellini
2015-11-10 12:32   ` Arnd Bergmann
2015-11-10 12:32     ` Arnd Bergmann
2015-11-10 14:43     ` Stefano Stabellini
2015-11-10 14:43       ` Stefano Stabellini
2015-11-10 14:43       ` Stefano Stabellini
2015-11-10 14:47       ` Arnd Bergmann
2015-11-10 14:47         ` Arnd Bergmann
2015-11-10 11:57 ` [PATCH v2 5/7] arm: extend pvclock_wall_clock with sec_hi Stefano Stabellini
2015-11-10 11:57   ` Stefano Stabellini
2015-11-10 11:57   ` Stefano Stabellini
2015-11-10 11:57 ` [PATCH v2 6/7] xen/arm: introduce xen_read_wallclock Stefano Stabellini
2015-11-10 11:57   ` Stefano Stabellini
2015-11-10 11:57   ` Stefano Stabellini
2015-11-10 12:35   ` Arnd Bergmann
2015-11-10 12:35     ` Arnd Bergmann
2015-11-10 11:57 ` [PATCH v2 7/7] xen/arm: set the system time in Xen via the XENPF_settime64 hypercall Stefano Stabellini
2015-11-10 11:57   ` Stefano Stabellini
2015-11-10 11:57   ` Stefano Stabellini
2015-11-10 12:39   ` Arnd Bergmann
2015-11-10 12:39     ` Arnd Bergmann
2015-11-10 15:58     ` Stefano Stabellini
2015-11-10 15:58       ` Stefano Stabellini
2015-11-10 15:58       ` Stefano Stabellini

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